Epigenetic estimation of age in humpback whales - data held at Dryad

Assays for human age have recently been developed recently based on age-induced changes in DNA methylation of specific genes. We used information on age-associated DNA methylation in human and mouse genes to identify homologous gene regions in humpbacks. Humpback skin samples were obtained from individuals with a known year of birth and employed to calibrate relationships between cytosine methylation and age.

Seven of 37 cytosines assayed for methylation level in humpback skin had significant age-related profiles. The three most age-informative cytosine markers were selected for a humpback epigenetic age assay. The assay has an R2 of 0.787 (p = 3.04e-16) and predicts age from skin samples with a standard deviation of 2.991 years.

The epigenetic method correctly determined which of parent-offspring pairs is the parent in more than 93% of cases. To demonstrate the potential of this technique, we constructed the first modern age profile of humpback whales off eastern Australia and compared the results to population structure five decades earlier. This is the first epigenetic age estimation method for a wild animal species and the approach we took for developing it can be applied to many other non model organisms.